Description: The activity of the Methodology Core informs and is motivated by the activities of all other Cores. This Core unit works to assure the methodological rigor of Center research and retains its original aims of conducting methodological research. Dr. Carole Siegel directs the Methodology Core, allocating a little over a third of her time (35% time) to this effort. In this resubmission, Eugene Laska joins the core as Co-director (10% time). The application lists 9 more faculty and staff (all part-time 5% to 25%) and 3 part-time research assistants. Funding is only requested for 4 individuals totaling 70% time. Additionally, $2,500 per year is requested for ?Quick Turnaround? consultants. The specific aims of this Core are to: 1. Ensure the methodological rigor of Center projects by new project review; 2. Develop methods for mental health services research for Core projects and general use; and 3. Maintain a quick-response capacity to develop policy relevant information through existing databases and innovative methodology approaches.